The first frame of the animation shows where the bird can find a suitable climate today (based on data from 2000). The next three frames predict where this bird’s suitable climate may shift in the future—one frame each for 2020, 2050, and 2080.

One of the most dramatic avian range expansions in recent history has been that of the Cave Swallow. Formerly unheard of in North America north of Florida and south Texas, the species is now a regular in small-to-medium flocks on fall migration north all the way to New England and the eastern Great Lakes. The birds tend to disappear by early winter, but the model predicts change in that regard. Audubon’s climate model projects a radical shift in winter climate space for this species, with only 6% of the current remaining stable by 2080. However, this species lives mostly south of the United States and Canada, and its prospects in Latin America and the Caribbean are not addressed by the model.

Species Range Change from 2000 to 2080

The size of the circles roughly indicates the species’ range size in 2000 (left) and 2080 (right).

The amount of overlap between the 2000 circle and the 2080 circle indicates how stable the range will be geographically. Lots of overlap means the bird’s range doesn’t shift much. No overlap means the species will leave its current range entirely.